Services on demand in mobile communications system

ABSTRACT

A method and an apparatus for implementing the method for using and implementing a service-on-demand in a mobile communication system. The services-on-demand are intended to be received by means of a mobile station. The mobile station monitors a cell transmission and receives parts intended for the mobile station from the transmission. In order to use the services-on-demand, in the method the service-on-demand is offered in the cell to all mobile stations located in the cell over a fist channel, a registration message ( 2 - 2 ) is transmitted from the mobile station for registering as a user of the service-on-demand over a signalling channel, an acknowledgement ( 2 - 4 ) of the registration, indicating how the service-on-demand is received, is received at the mobile station, and the reception of the service-on-demand is started over the first channel in a manner indicated by the registration acknowledgement.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 09/668,315filed Sep. 22, 2000, which in turn is a continuation of InternationalApplication No. PCT/FI99/00229 filed Mar. 23, 1999. The contents ofthese applications are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

The invention relates to services conveyed to subscribers via a mobilecommunication system, and particularly to services-on-demand for whichthe subscriber is charged.

In connection with fixed networks, various broadcast services have beenimplemented to be used by a user when desired, such as avideo-on-demand, for example. The subscriber generally pays for such aservice according to use. Below, such services will be calledservices-on-demand. In a fixed network, a subscription service can bereadily broadcast and subscribers for these services can be readilycharged since the service-on-demand is provided at a particularstationary location of use in accordance with an agreement.

The problem presented by the arrangement described above is, however,that it cannot be implemented as such in mobile communication systemswherein the subscriber can freely move in the system area. Prior artmobile communication systems have services liable to charges availablebut the services are based on point-to-point transmissions, which burdenthe network. Broadcasts implemented in mobile communication systems arecell-specific cell broadcasts containing information intended for allmobile stations located in the cell. For example the pan-European GSM(Global System for Mobile Communication) system defines, in addition tocell broadcast, transmission modes of broadcast nature, such aspoint-to-multipoint transmission wherein a message is transmitted to allsubscribers or predetermined subscriber groups in an area and at amoment determined by the message transmitter. In ‘multicast’, a specialform of the point-to-multipoint transmission, a message is transmittedto the subscribers located at a particular moment in a particulargeographical area. The transmitted message includes a group identifier,and only those subscribers that belong to the group receive the message.These transmission modes are not, however, suitable for implementingservices-on-demand since the reception moment of the message isdetermined by the transmitter, who is also charged.

BRIEF DESCRIPTION OF THE INVENTION

An object of the invention is thus to provide a method and an apparatusimplementing the method to enable services-on-demand to be offeredwithout point-to-point transmissions also in a mobile communicationsystem. The objects of the invention are achieved by the method beingcharacterized by offering in the cell the service-on-demand to allmobile stations located in the cell over a first channel, transmittingfrom the mobile station a registration message for registering as a userof the service-on-demand over a signalling channel, receiving at themobile station an acknowledgement of the registration, which indicateshow the service-on-demand is received, and starting to receive theservice-on-demand over the first channel in a manner indicated by saidacknowledgement message.

Registration herein refers to all method steps that are necessary foridentifying the service-on-demand used and for identifying the user suchthat the mobile communication network or the service provider obtainsthe subscriber information that enables charging for the use. It issufficient for the registration message to indicate that the userdesires to register, however.

The invention further relates to a mobile communication system whereinthe method of the invention can be utilized. The mobile communicationsystem in accordance with the invention is characterized by furthercomprising at least one on-demand-service centre for offering at leastone service-on-demand via the base transceiver stations in the servicearea of the service-on-demand over cell-specific first channels to allmobile stations located in the service area, for receiving theregistration of users of the service-on-demand and acknowledging theregistration, at least one mobile station being arranged to register asa user of the service-on-demand by transmitting a registration messageover a signalling channel, to receive an acknowledgement of theregistration, and to start receiving the service-on-demand over a firstchannel of the location cell as indicated by information included insaid acknowledgement, and to convey the service-on-demand to the user.

The invention further relates to a mobile station which can be utilizedin the method and system of the invention. The mobile station of theinvention is characterized by comprising registration means forcomposing and transmitting a registration message to the mobilecommunication network over a signalling channel, said registrationmessage indicating that the user of the mobile station desires toregister as a user of a service-on-demand available at the location celland for receiving an acknowledgement of the registration, and servicemeans responsive to the acknowledgement for receiving theservice-on-demand as indicated by the acknowledgement and for conveyingthe service to the user interface.

The invention further relates to an on-demand-service centre which canbe utilized in the method and system of the invention. Theon-demand-service centre of the invention is characterized by comprisingservice means for offering at least one service-on-demand to a servicearea comprising at least one cell of the mobile communication system,registration means for receiving and acknowledging the registration of auser of the service-on-demand, and charging means responsive to theregistration means for charging the user of the service-on-demand forthe use.

The invention further relates to a base transceiver station which can beutilized in the method and system of the invention. The base transceiverstation of the invention is characterized by being arranged to transmitat least one service-on-demand over one of its channels, theservice-on-demand being available for all mobile stations located in thecell.

The invention is based on the idea that a service-on-demand liable tocharges is transmitted in a cell, the service-on-demand being availableonce a user is registered as the user of the service-on-demand in thecell.

An advantage of the invention is that a service liable to charges can beprovided cost-effectively, saving radio resources and network capacity.A service provider can reach several users with one transmission. Afurther advantage is that the user does not have to subscribe to theservice in advance or belong to predetermined group, but he or she canstart using any service available at his or her current location cellwhenever he or she desires—irrespective of how many users are using theservice on the same channel at the same cell. Since registration as aservice user is initiated on a signalling channel and the service istransmitted over another channel of the cell, the registration can beperformed by common call-setup signalling and the service-on-demand canbe transmitted in each cell over the most appropriate channel as regardsthe system. Furthermore, another advantage is that the mobile stationdoes not know the channel over which the service-on-demand istransmitted without the registration.

In a preferred embodiment of the invention, the service-on-demandtransmitted is encrypted, and a key whereby the encryption can bedecrypted is transmitted to the mobile station, the advantage of thisbeing the fact that unauthorized use of the service can thus beprohibited.

In a preferred embodiment of the invention, the on-demand-service centretransmits the service-on-demand only when the service-on-demand has atleast one user, the advantage of this being the fact that unnecessaryload on the system can thus be avoided.

Preferred embodiments of the method, system, mobile station,on-demand-service centre and base transceiver station of the inventionare disclosed in the attached dependent claims.

LIST OF FIGURES

The invention is now described in closer detail in connection with thepreferred embodiments with reference to the accompanying drawings, inwhich

FIG. 1 shows a simplified block diagram of a mobile communicationsystem,

FIG. 2 shows signalling in accordance with a first preferred embodimentof the invention,

FIG. 3 shows signalling in accordance with a second preferred embodimentof the invention,

FIG. 4 shows a simple block diagram of a mobile station of theinvention, and

FIG. 5 shows a simple block diagram of a on-demand-service centre inaccordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention can be applied in connection with any cellularmobile communication system, for example the third generation mobilecommunication system being developed, called the UTMS (Universal MobileTelephone System). The invention is particularly well suited for beingimplemented in connection with packet data systems offering broadbanddata transfer. Such systems include the UTMS and the GPRS (GeneralPacket Radio Service) for example, which is a new service for the GSMsystem and a subject matter of the GSM phase 2+standardization work inthe ETSI (European Telecommunication Standard Institute). The GPRSservice enables packet data transfer between mobile data terminalequipment and external data networks with the GSM network serving as anaccess network. The preferred embodiments of the invention will bedescribed in the following by means of a GPRS packet radio networkformed as a combination of a GPRS service and a GSM network, withoutrestricting the invention to such a packet radio system, however. Thedefinitions of mobile communication systems in general, and of the GPRSand UMTS systems in particular are developing rapidly. Consequently, allwords and expressions should be interpreted in a wide sense, ratherbeing intended to illustrate than restrict the invention. Essential tothe invention is the function, not the element in which the function isperformed.

FIG. 1 illustrates a mobile communication system which is a GPRS packetradio network implemented in the GSM system. It is to be noted that thepacket radio network only provides the physical connection between auser of a service-on-demand and an on-demand-service centre, the exactoperation and structure of the network being irrelevant to theinvention. A GPRS service 1 comprises gateway support nodes, varioussub-network service areas, serving GPRS support nodes SGSN, trunknetworks and connections to other data networks. The structure of theGPRS network is not shown in detail in FIG. 1. In the UTMS system thenode corresponding to the SGSN is a packet data access node PDAN.

Each serving support node SGSN of the GPRS service 1 is connected to theGSM mobile communication system so as to enable the serving support nodeto offer a packet data service to mobile data terminal equipment via aplurality of base transceiver stations, i.e. cells C. In the example ofFIG. 1, the SGSN is connected to a base station controller BSC. Themobile communication network in between provides packet switched datatransfer between the support node and the mobile data terminalequipment. Each support node SGSN manages the packet data service in thearea of one or more cells C in a packet radio network of the cellulartype. The radio cells C slightly overlap each other although in FIG. 1they are, for the sake of clarity, presented as having clear boundaries.Neither is the shape of the cells in practice as regular as in FIG. 1. Amobile station MS is connected to a base transceiver station BTS, in thecase of FIG. 1 to the base transceiver BTS1, via a radio path. There isgenerally one base transceiver station BTS provided per one cell C. Themobile station MS located in the cell communicates via the mobilecommunication network with the support node SGSN to whose service areathe cell belongs. In principle, the mobile communication network betweenthe support node SGSN and the mobile station MS only conveys packetsbetween these two. Consequently, the mobile communication networkprovides packet switched transfer of data packets between the mobilestation MS and the serving support node SGSN.

Under the control of the base station controller BSC in the GSM networkthere is usually a plurality of base transceiver stations BTS. The basestation controller BSC is responsible for managing the radio frequenciesand radio channels used by the base transceiver station BTS. Under thecontrol of a mobile switching centre MSC there is usually a plurality ofbase station controllers BSC. The mobile switching centre MSC isconnected for instance to other mobile switching centres, a publictelephone network and other mobile telephone networks and variousservice centres, which are not shown in FIG. 1. As subscriber registersthe GSM network has at least a home location register HLR and a visitorlocation register VLR. Subscriber information on all subscribers in thenetwork is stored permanently or semi-permanently in the home locationregister HLR. Normally it is the subscriber who is charged; the mobilestation can be used by another person. The home location register,together with the mobile switching centre, collects billing informationwhich is transmitted to a separate billing centre (not shown in thefigure). The home location register HLR of the GSM network comprises theGPRS subscriber information and routing information. The visitorlocation register VLR is of another type; it is usually connected to onemobile switching centre MSC, but it is also able to serve severalcentres. When the mobile station MS is active (it is registered in thenetwork and can initiate or receive a call), most of the subscriberinformation concerning the mobile station MS included in the homelocation register HLR is loaded (copied) into the visitor locationregister VLR of the mobile switching centre MSC in the area of which themobile station MS is located.

The base transceiver stations BTS continually transmit information aboutthemselves and the environment over the cell broadcast channel asgeneral information. The mobile station MS receives only one cellbroadcast channel of the base transceiver station BTS, called a servingbase transceiver station, at a time. The base station controllers BSCmanage the messages on the cell-specific cell broadcast channels of thebase transceiver stations. The base station controller BSC conveys thebroadcast messages intended for each single base transceiver station BTSon the basis of information fed by the operator. The base stationcontroller BSC can also be responsible for delivering messagesassociated with the services-on-demand to correct base transceiverstations and it can thus have information composed on each cell'sservices-on-demand. The SGSN can also be responsible for the above tasksand contain the information on the services-on-demand of the cells inits area.

The mobile communication system of the invention further comprises atleast one on-demand-service centre ODSC, which is for instanceassociated with the GPRS service 1. Alternatively, it could also beconnected to any mobile switching centre MSC. The on-demand-servicecentre ODSC is not necessarily one entity but it can comprise functionsdistributed to different units; for instance the mobile switching centreand the home location register can be responsible for charging for theuse of a service, the mobile switching centre and the visitor locationregister for accepting the registration, the base station controller orthe SGSN for conveying the services-on-demand to the base transceiverstations, and the base transceiver station for encrypting the servicebefore the transmission. For the sake of clarity, however, theon-demand-service centre will be dealt with as one entity below. Theon-demand-service centre will be discussed in closer detail inconnection with FIG. 5.

The on-demand-service centre ODSC can produce various services. A uniqueservice area is usually defined for each service. The service area mustcover at least one cell C, and at its largest it may comprise the entiresystem. With appropriately defined service areas for instance weatherreports can be offered locally and a video-on-demand service over thewhole network area. The services-on-demand at each cell are thusindependent from each other. A cell C3 in FIG. 1 can have theservice-on-demand 1 available and a cell C1 can have services-on-demand2 and 3 available, for example. The channel the service-on-demand usesis usually determined cell-specifically by the operator. A uniquetransmission channel can be allocated to each service-on-demand.Alternatively, some or all services-on-demand can be transmitted on thesame transmission channel. Minor services-on-demand, such as weatherreports, can be transmitted over the on-demand-channel with otherinformation, in which case they save the radio interface resources. Thechannel over which the service-on-demand is transmitted will be calledan on-demand-service channel below. Prior art transmission channelsinclude the broadcast channel whose transmissions can be received by allmobile stations, and connection-specific transmission channels. Theon-demand-transmission channel differs from the broadcast channel insuch a way that the transmissions of the on-demand transmission channelcan only be received by registered users. From the connection-specifictransmission channel the on-demand-channel differs such that itstransmissions can be received by more than one mobile station and noend-to-end connection is necessary for allocating the channel. Thesystem does not normally expect to receive signalling messages over theon-demand-service channel, but in some embodiments signalling messagescan be transmitted. Depending on the nature of the service, theon-demand-service channel can also be duplex.

FIG. 2 shows a signalling diagram of a first preferred embodiment of theinvention. A mobile station MS is registered for the first time in acell, for example in a cell C1 in the case of FIG. 1, and receivesinformation on the available services-on-demand at the cell in a message2-1 over the cell broadcast channel of a serving base transceiverstation, a base transceiver BTS1 in the case of FIG. 1. The user of themobile station selects the service he or she desires and gives themobile station a command to register as a user of the service. Themobile station transmits the necessary information for identifying thesubscriber and the information on the selected service, for example aservice 2, in a registration message 2-2 over a signalling channel. Thebase transceiver station receives the message 2-2 and forwards it to anon-demand-service centre ODSC, which registers the fact that thesubscriber starts using the service 2 and transmits an acknowledgementof the registration to the base transceiver station in a message 2-3.The base transceiver station adds to the message 2-3 a key whereby theencryption of the service-on-demand can be decrypted and transmits theacknowledgement and the key in a message 2-4 to the mobile station. Inother embodiments the key can be already in the message 2-3, in whichcase the base transceiver station only forwards that message instead ofthe message 2-4. The base transceiver station transmits to the mobilestation the information about the channel over which theservice-on-demand is transmitted either in the message 2-4 or before itin a separate message. The mobile station receives the acknowledgementand separates from the acknowledgement the key and the on-demand-servicechannel definition information possibly included in the acknowledgement.Next, the mobile station receives and decrypts the service transmittedencrypted on the on-demand-service channel and conveys the service tothe user of the mobile station at point 2-5. In the first preferredembodiment the base transceiver station encrypts the service-on-demandbefore transmitting it. Since encrypting and adding the key only takeplace as late as at the base transceiver station, the network load canbe kept to a minimum. In another embodiment the transmission centre cantransmit the service-on-demand to the network encrypted. The advantageof the centralized encryption lies in the fact that the encryptionalgorithm is computed only once in the network. In addition, thecentralized encryption enables for example the use of receiver-specificencryption.

When the user of the mobile station no longer desires to use theservice, he or she gives the mobile station a termination command viathe interface. In the first preferred embodiment the mobile stationtransmits information about terminating the service, i.e. cancelling theregistration, in a message 2-6 on the signalling channel. The mobilestation simultaneously stops using (point 2-5) the service, i.e.decrypting and conveying the service to the user of the mobile station.The base transceiver station conveys the message 2-6 to theon-demand-service centre, which registers the termination of use andcreates a toll ticket in order to charge the subscriber for the serviceused. In another embodiment, the on-demand-service centre canacknowledge the termination message and the mobile station can stopusing (point 2-5) the service-on-demand only as a response to theacknowledgement. When receiver-specific encryption is used, theon-demand-service centre can change the encryption of theservice-on-demand after receiving the message 2-6 such that the mobilestation can no longer receive it. Alternatively, the mobile stationmoves to receive another channel and/or sets to zero the information inthe memory necessary for the reception.

FIG. 3 shows a signalling diagram of a second preferred embodiment ofthe invention. The user of a mobile station requests for informationabout available services-on-demand at the cell, the mobile station MSthus transmitting a message 3-1 requesting for the services-on-demandpreferably over a signalling channel. A base transceiver station BTSidentifies the message 3-1 and replies to the message by transmitting tothe mobile station a message 3-2 wherein the services-on-demandavailable at the cell are listed. In another embodiment the basetransceiver station can convey the request to an on-demand-servicecentre, a support node SGSN or a base station controller, which repliesto the mobile station via the base transceiver station. The user selectsa desired service among the services, for instance a service 3, andgives the mobile station a command to register as a user of the service.The mobile station transmits the information necessary for identifyingthe subscriber and information on the selected service, in the presentexample the service 3, in a message 3-3 over the signalling channel. Thebase transceiver station receives the message 3-3 and forwards it to theon-demand-service centre ODSC. The on-demand-service centre checks thesubscriber information from the home location register and detects thatthe subscriber has agreed to prepay for the service used. The subscriberhas x FIM available on his or her service account. The on-demand-servicecentre computes that the service 3 can be used for y minutes for thatsum of money. Next, the on-demand-service centre registers that thesubscriber starts using the service 3 and transmits an acknowledgementof the registration, the maximum time y for the use and a decryption keyof the service-on-demand encryption to the base transceiver station in amessage 3-4. The base transceiver station adds to the message 3-4 acommand to move so as to start receiving the channel over which theservice 3 is transmitted, and transmits a message 3-5 to the mobilestation. The mobile station receives the acknowledgement, separates thekey and the maximum time y from the acknowledgement and moves to receivethe on-demand-service channel included in the message. Next, at point3-6, the mobile station uses, i.e. receives and decrypts the servicetransmitted encrypted and conveys the service to the user of the mobilestation. The mobile station simultaneously monitors when the maximumtime expires. If no termination command is received from the user, themobile station stops using the service at point 3-7 and exits thechannel once the maximum time y expires. If the on-demand-service centredoes not receive the termination message before the maximum timeexpires, it sets the balance of the subscriber's service account to 0FIM.

In another preferred embodiment the on-demand-service centre can, afterreceiving the message 3-3, inquire of the user via the mobile stationhow long he or she desires to use the services or how much money he orshe desires to spend on the services. The mobile station transmits areply to the on-demand-service centre, which indicates in the message3-4 how long the service can be received. The on-demand-service centresimultaneously sends a bill. When a prepaid subscriber card is used—anSIM card in the GSM system—information about how much money can be spentis added to the message 33, for instance. When the prepaid subscribercard is used, the use of the service-on-demand is charged bydecrementing the sum of money on the subscriber card.

In one preferred embodiment the user of the mobile station can transmitinformation on how long he or she desires to use the service or how muchmoney he or she desires to spend on the services already in the message3-3. Hence, the mobile station can identify the time and sum of moneyalready from the information given by the user, in which case it is notnecessary to indicate the time in the message 3-4.

In one preferred embodiment the on-demand-service centre does nottransmit the maximum time y of use to the mobile station in the message3-4, but monitors the expiration of the time itself. At the expirationof the desired/paid time, the on-demand-service centre transmits thetermination command to the mobile station. The termination command ispreferably transmitted as a message directed to the mobile station overthe signalling channel since other information can also be transmittedamong the service-on-demand. The mobile station stops conveying theservice after receiving the termination command. The termination commandcan also be a command indicating that the mobile station should move andstart receiving another channel than the one transmitting theservice-on-demand. No separate termination command is necessary ifreceiver-specific encryption is used. When the encryption is changedonce the time has expired, the receiver is no longer able to decrypt theservice-on-demand. Furthermore, no separate termination command isrequired when an encryption method wherein each receiver has a uniqueencryption field is used. As a result from setting the encryption fieldto zero the receiver can no longer receive the transmission.

The signalling messages described above in connection with FIGS. 2 and 3are only given by way of example and may comprise several separatemessages for conveying the same information. In addition, the messagesmay comprise further information, and they can also be freely combined.Depending on the operator and the system, also other network elements towhich different functions have been distributed can participate inconveying and signalling the information. Also other channels than thosementioned above can be used for conveying the messages. Differentembodiments can be combined. The service-on-demand can be alsotransmitted without encryption over a channel allocated to theparticular service only, in which case no keys need be transmitted inthe registration acknowledgements. The service-on-demand can also betransmitted over the on-demand-service channel or over the broadcastchannel, equipped with a service identifier. In such a case, a groupidentifier is transmitted to the mobile station to serve as the key withwhich the mobile station can select the correct messages. Essential isthat a piece of information which enables the service to be used isconveyed in the registration acknowledgement. At its simplest theinformation is the channel over which the service-on-demand istransmitted, or only the group identifier. Alternatively, information onthe services available at the cell can also be requested by calling aseparate switching centre, or the cell can transmit the information asbroadcast short messages for instance at every half an hour. Theon-demand-service channel can also have an open announcement field,which all mobile stations in the cell can follow and which comprisesadvertisements for the services-on-demand.

FIG. 4 shows a simple block diagram of a mobile station MS in accordancewith the invention. In the GSM system, the mobile station MS comprisesactual terminal equipment and a detachable subscriber identity moduleSIM attached thereto. In the UMTS system the corresponding identitymodule is called a USIM. In the GSM system, the SIM (Subscriber IdentityModule) card used to identify the subscriber is a processor card, i.e. asmart card, to be positioned in the mobile station and comprising forinstance information associated with identifying the subscriber, such asan IMSI (International Mobile Subscriber Identity) number to identifythe mobile station subscriber, and a certain capacity of memory M2. Theactual terminal comprises a transceiver Tx/Rx with its antennas, a userinterface UI, a controller CP and memory M1. The memory of the mobilestation thus comprises two parts: memory M1 of the terminal and memoryM2 of the SIM card.

The user interface UI usually comprises a keypad, a display, aloudspeaker and a microphone, which are not shown in FIG. 2. The userinterface can also comprise a computer with its terminal, a televisionor a radio, connected to the mobile station for receiving theservice-on-demand. The user interface UI allows the user to giveinstructions and commands to the controller CP and receive informationconveyed by the mobile communication system. The user interface UI alsoallows the user of the mobile station to receive information on theservices-on-demand, give a command to register as a user of theservice-on-demand, receive the service-on-demand and give a command tostop receiving the service-on-demand.

The controller CP receives from the user interface for instance theabove inputs associated with the use of services-on-demand. Thecontroller CP can indicate the available services-on-demand at the cellto the user of the mobile station for instance with an audio signal anda message or a character appearing on the display. The controller CP canalso issue audio signals, help texts or help characters associated withthe operation of the mobile station and/or the mobile communicationsystem to the user of the mobile station via the interface and conveythe possible responses received to the mobile communication system.

The controller receives and transmits for instancesignalling/controlling messages, such as messages associated with userregistration and termination of the service-on-demand, and asubscription service of the cell via the transceiver Tx/Rx. Thecontroller also receives the cell broadcast via the transceiver. From anacknowledgement associated with registration in the service-on-demandthe controller separates an instruction indicating how theservice-on-demand is received. The instruction can be only a piece ofinformation about the transmission channel or a key, or a combination ofthe two. The controller can separate from the acknowledgement associatedwith the registration the transmission decryption key and use the key todecrypt the service-on-demand transmitted encrypted. As the key, thecontroller can separate a group code, and subsequently, receive theservices-on-demand equipped with the particular code from the broadcastor the on-demand-service channel transmission and convey the services tothe user. The controller can receive information on the subscriptionservices of the cell over the cell broadcast channel or from the openfield of the on-demand-services channel. The controller receives theservices-on-demand over the on-demand-services channel over which thebase transceiver station transmits the service used and which channelthe mobile station is instructed to receive in connection withregistration. The on-demand-service channel can also be the cellbroadcast channel. The controller can also be responsible for theservice-on-demand being received only for a certain time. Furthermore,besides from the user, the controller can receive theinstruction/command to stop receiving and conveying theservice-on-demand also from the mobile communication system. Thecontroller can remove the decryption key or the group code from its usein response to the termination command/instruction.

The controller can separate from the cell broadcast the servicesavailable at the cell and display them to the user via the userinterface of the mobile station. The controller can be arranged todisplay the services either at the request of the user of the mobilestation or at the first registration of the mobile station in the cell.The controller can also be arranged to compose a message requesting forinformation on the services-on-demand available at the cell when theuser of the mobile station desires information on the services-on-demandavailable.

FIG. 5 shows a simple block diagram of an on-demand-service centre ODSCin accordance with the invention. The on-demand-service centre ODSC doesnot necessarily consist of one entity, as shown in FIG. 5, but it cancomprise decentralized functions positioned in different units, asexplained in connection with FIG. 1. The on-demand-service centre ODSCcomprises at least one service part SP, which comprises the receivingpart and the transmitting part of the service-on-demand. The servicepart allows the service to be conveyed to the network, for example tothe GPRS packet radio network or the UMTS network. Each separateservice-on-demand preferably has a unique service part. Theon-demand-service centre ODSC can comprise connection parts L1 (only oneshown in the figure) for connecting the on-demand-service centre toother networks or service centres. The on-demand-service centrecomprises a registration part RP for receiving and acknowledging theregistration of the users of the service-on-demand, and a billing partBP for charging for the use of the service-on-demand. Theon-demand-service centre ODSC can further comprise memory M for instancefor storing the encryption keys of the different services or formaintaining the cell-specific lists of services-on-demand. The serviceareas of each service-on-demand transmitted from the on-demand-servicecentre can also be stored in the memory M. In addition to these, theon-demand-service centre can comprise a generation part GP of themessage for generating short messages for instance while replying to amessage requesting for the services-on-demand available at the cell.

The receiving part of the service part SP of the on-demand-servicecentre ODSC in accordance with the invention receives theservice-on-demand from the service provider. Correspondingly, thetransmitting part transmits the service-on-demand to those basetransceiver stations of the mobile communication system that belong tothe service area of the service in question. Instead of the basetransceiver stations, the service can be transmitted to base stationcontrollers or serving nodes, which are responsible for forwarding theservice-on-demand to the correct base transceiver stations according tothe instructions given by the operator. The serving nodes include forexample the SGSN of the GPRS network and the PDAN of the UMTS network.Depending on the embodiment, the transmitting part transmits theservice-on-demand either without encryption or encrypts theservice-on-demand before transmitting it. To arrange the encryption in acentralized manner has the advantage that the same encryption can beapplied to thousands of users, if desired, and still each user'sreceiver can be provided with a unique receiver-specific key which canbe used for decryption only by the user's receiver in question. Theencryption ensures that the service-on-demand is only used viaregistered mobile stations.

The registration part RP of the on-demand-service centre ODSC identifiesa registration message transmitted from the mobile station, identifiesthe service in which the mobile station desires to register, and thesubscriber of the mobile station to be able to perform the charging. Ifthe registration is accepted, the register part transmits anacknowledgement to the mobile station which requested for theregistration. The registration part RP can be arranged to find out fromthe home location register or the identification unit of the mobilestation whether the subscriber is a prepaying subscriber and if so, tofind out the remaining sum of the prepayment. The registration part RPcomputes how long the service can be used on the basis of the remainingsum of the prepayment and the listed price of the service, and eitherconveys this information to the mobile station in the messagesassociated with registration or, after the time in question is expired,transmits a termination command to stop using the service to the mobilestation. The registration part RP can be arranged to check for instancefrom the home location register whether the desired service-on-demand ispermitted to the user and deny the registration if the service is notpermitted. In connection with registration, the registration part canalso consult the user of the mobile station or the mobile station abouthow long the service is desired to/can be used and/or how much the useof the service may cost. If, in connection with registration, the userhas indicated the time or the sum of money the user desires to spend onthe service-on-demand, the registration part RP can also be arranged toseparate this information from the registration message. In such casesthe registration part can serve to watch that the permissible limits arenot exceeded, for example as described in connection with FIG. 3. Whenan encrypted service-on-demand is used, the registration part adds tothe acknowledgement a decryption key of the service-on-demand, which canbe shared by all users or which can be user-specific. When theuser-specific encryption is used and the use of the service isterminated, the registration part can give the transmitting part acommand to change the encryption such that the user who has stoppedusing the service can no longer receive it.

The billing part BP of the on-demand-service centre starts charging thesubscriber for the service as soon as the billing part receives theinformation from the registration part that the service has been put touse and correspondingly, the billing part BP stops charging thesubscriber as soon as the billing part receives the information from theregistration part that the service is no longer used. After terminatingthe charging, the billing part either transmits the information on thesum of the bill to some part of the system, or adds the information to abill to be sent to the subscriber himself or herself. The billing partcan maintain information on the number of users using the service at theparticular moment, and even modify the price of the service accordingthe number of users. In the first preferred embodiment the number of theusers using the service also controls the transmitting part of theservice part. If there are no registered users of a service, no serviceis transmitted. One registered user of the service suffices to cause theservice to be transmitted. The number of the service users can bemonitored service-area-specifically or cell-specifically.

The base transceiver station of the present invention does notnecessitate any great changes in the prior art base transceiver stationstructure. The base transceiver station of the invention is arranged toreceive a service-on-demand from the on-demand-service centre andtransmit the service as a service-on-demand over one of its channels.The base transceiver station can receive the service-on-demand from aplurality of on-demand-service centres and/or a plurality ofservices-on-demand from one on-demand-service centre and transmit eachservice-on-demand over the channel allocated to the service at the basetransceiver station. In addition, the base transceiver station can bearranged to encrypt the service-on-demand before it is transmitted overthe channel allocated to the service. The base transceiver station canalso be arranged to add the decryption key to the registrationacknowledgement. Furthermore, the base transceiver station can bearranged to transmit information on the available services-on-demand atthe cell in the cell broadcast. This information is either composed byitself or requested for from the base station controller, theon-demand-service centre or the serving node, such as the SGSN of theGPRS network or the PDAN of the UMTS network, for instance. The basetransceiver station can be arranged to identify the signalling messagerequesting for the services-on-demand available at the cell and transmitthe information on the available services-on-demand at the cell to themobile station as a short message. The base transceiver station of theinvention can be arranged to transmit the service-on-demand also overthe cell broadcast channel among general information.

It is to be understood that the above description and the accompanyingdrawings are only intended to illustrate the present invention. It willbe obvious to those skilled in the art that the invention can be variedand modified in many ways without departing from the scope and sprit ofthe invention disclosed in the attached claims.

1. An on-demand-service centre in a mobile communication system,comprising: service means for offering at least one service-on-demand toa service area which comprises at least one mobile communication systemcell, registration means for receiving and acknowledging theregistration of a user of the service-on-demand, and billing meansresponsive to the registration means for charging the user for the useof the service-on-demand.
 2. An on-demand-service centre (ODSC) asclaimed in claim 1, wherein the service means are arranged to encryptthe service-on-demand, and the registration means are arranged toinclude a key in the registration acknowledgement.
 3. Anon-demand-service centre as claimed in claim 1, wherein the registrationmeans are arranged to compute the number of the service-on-demand users,and the service means are arranged to transmit the service-on-demand ifthere is at least one user of the service-on-demand.
 4. A basetransceiver station comprising channels for at least one cell, one ofthe channels being a cell-specific broadcast channel for transmittinggeneral information to mobile stations in the cell, the base transceiverstation being arranged to transmit at least one service-on-demand overone of its channels, the channel being other than the cell-specificbroadcast channel for general information, the service-on-demand beingavailable on said other channel to all mobile stations located in thecell.
 5. A base transceiver station as claimed in claim 4, wherein thebase transceiver station is arranged to transmit in the generalinformation of the cell a notification of the services-on-demandavailable at the cell.